Substituted silicon acylates



Patented Jan. 9, 1951 UNITED STATES PATENT OFFICE SUBSTITUTED SILICON ACYLATES No Drawing. Application July 16, 1946, Serial N0. 683,984

26 Claims.

This invention relates to substituted silicon acylates and their preparation, and more particularly to such silicon acylates containing substituent organic groups.

Among the objects of the present invention is the production of silicon acylates containing substituent organic groups attached to the silicon.

Further objects include methods for the preparation of the acylates. I

Further objects include hydrolysis products of such acylates and compositions containing the acylates and their hydrolysis products.

Still further objects and advantages of the present invention will appear from the more detailed description set forth below, it being understood that this more detailed description is given by way of illustration and explanation only, and not by way of limitation since various changes therein may be made by those skilled in the art without departing from the scope and spirit of the present invention.

In accordance with the present invention, substituted silicon acylates of carboxylic acids are prepared from an organo substituted silicon halide and a carboxylic acylating agent such as an organic carboxylic acid or a salt thereof.

The organo substituted silicon halide employed includes a variety of such compounds or mixture of such compounds, including organo substituted halogen silanes and organo substituted silicohaloforms such as silicochloroform. The halide may be any reactive halide including particularly the chlor and bromine derivatives. The substituent organo group in such compounds may be aliphatic or unsaturated aliphatic groups such as the alkyls including methyl, ethyl, propyl such as normal propyl, butyl such as normal butyl, pentyl, hexyl such as normal hexyl, and. unsaturated aliphatic groups including both olefinic and acetylenic linkages illustrated for example, by the allyl group; or the substituent organo group may be alicyclic such as cyclohexyl or may be aryl such as phenyl, and the substituent organo groups present may contain substituents themselves such as halogen, etc., but no substituent group should be present in the organo group attached to the silicon which would interfere with the reaction involved.

The carboxylic acylating agent includes the carboxylic acids particularly of aliphatic and aromatic character and their anhydrides and salts, as for example, the alkali metal salts and also substituted. acids and their salts where there is no substituent group in the acid which reacts with the silicon halide under the conditions employed. The acids may be monocarboxylic or polycarboxylic but monocarboxylic acids are preferred. Representing the aliphatic monocarboxylic acids there may be mentioned particularly the fatty acids such as formic, acetic and propionic acids, and illustrative of the aromatic acids is benzoic acid.

The above mentioned reactants may be caused I to react directly, either at ordinary or room temperatures or at elevated temperature as by heating the reaction mixtures or carrying out the reaction desirably under refluxing conditions. Direct reaction with the acids may readily take place, whereas with the salts elevated temperatures are employed. Thus temperatures of from to C. or other temperatures which produce refluxing may be utilized depending on the particular materials undergoing reaction. Hydrogen chloride or other analogous materials formed in the reaction may be removed from the reaction zone, as for example, by an inert gas such 'as nitrogen.

While the reactants may be made to react directly in the absence of any added materials, the reaction may desirably be carried out in the presence of organic liquid vehicles, particularly organic solvent liquids which are a solvent for at least one of the reactants employed. If desired, the organic liquid present may be chosen from the standpoint of solubility of the acylate produced. Thus solvents may be used in which the initial reagents are soluble but the final product is insoluble or a solvent may be used in which the initial reagents and final product are insoluble. Organic liquid solvents include pentane, ethyl bromide, isopropyl ether, benzene, toluene, and carbon tetrachloride.

With silicochloroform, it has been found that regardless of the amount of acid used, some tetra acylate forms. When organo substituted silicochloroform or similar haloform is utilized as a reactant, such as butyl silicochloroform, certainly the major product obtained is the diacylate. Thus butyl silicochloroform and the acetic acylatinghydrogen or an organo group such as alkyl or aryl as set forth above, and may be the same as or different from R and R, and Y is halogen, particularly chlorine, a is from 1 to 3, and b is from to 1, c is from 0 to 1, and. a+b+c is equal to, or less than 3. Thus for the organo substituted halides which contain no hydrogen attached to the silicon, the formula of the halide would be RaR'bSiY(4-a-b), where R, R, Y, a and b have the values set forth above. In the silicochloroform and related derivatives, the halide would have the formulation RaR'bSiHYCl-a-b), where R, R and Y have the values set forth above, while a is from 1 to 2, and b is from 0 to 1.

The substituted acylates produced in accordance with the present invention may be generally formulated as RaR'bR"cSiZ(4-abc), in which R is an organo group such as alkyl or aryl as set forth above, R is an organo group such as alkyl or aryl as set forth above, and R" is hydrogen or an organo group such as alkyl or aryl as set forth above, and Z is a carboxylic acyl group, a is from 1 to 3, b is from 0 to 1, c is from 0 to 1, while a+b+c is equal to, or less than 3. R, R and R" may be the same or different groups. Where no hydrogen is attached to the silicon, the acylates will have the formula RaR'bSiZM-a-b), where these terms have the values set forth immediately above. In the silicochloroform derived acylates and similar materials, the acylates will have the general formula RaR'bSiHZ(3a-b), where R, R and Z have the values set forth above, while a is from 1 to 2, and b is from 0 to 1.

The acylates produced in accordance with the present invention have a variety of uses based on both expected and unexpected properties of such compounds. Thus some of the acylates such as ethyl silicon triacetate may be readily hydrolyzed by shaking with water to produce acetic acid and a colloidally dispersed ethyl silicone. The silicon containing material may be precipitated by removing part of the water, as for example, by distillation, or a rapid precipitation of the silicon materials may be obtained by the addition of ammonium hydroxide to the colloidal product. Similarly, diethyl diacetoxysilane may be hydrolyzed to give a colloidally dispersed diethyl silicone althoughdiethyl silanediol may also be present to some extent. Thus generally colloidal dispersions may be produced by mixing the acylates with water from which colloidal solutions or dispersions precipitation may be produced by removal of water or by the addition of ammonium hydroxide.

The acylates produced in accordance with the present invention may be utilized either by themselves or in solution for the preparation of other types of silicon derivatives or for addition and utilization in coating compositions, lubricating oils, molding compositions, coatings for text les, paper and related materials, in the production of laminated articles, etc.

The following examples will illustrate the invention, the parts being by weight unless otherwise indicated.

The first example describes the preparation of ethyl silicon triacetate by the action of acetic acid on ethyltrichlorosilane.

Example 1.In a 300 ml. flask was placed a mixture of 20.5 g. of ethyl trichlorosilane, 22.2 g. of acetic acid and 40 ml. of pentane. A reflux condenser, with a calcium chloride drying tube attached to one end of it, wa connected to the flask and the mixture was then heated until gentle refluxing took place. The heating was continued until the evolution of hydrogen chloride ceased (about 12 hours). The reaction product was subjected to distillation and there was obtained a 46% yield of ethyl silicon triacetate, B. P. 100- 102 C. at 4 mm. Analytical data for ethyl silicon triacetate:

Equivalent wt.: Calc. '78, found '77 Percent silicon: Calc. 12.0, found 12.3 Mol. weight: Calc. 234, found 223 When a small sample of the ethyl silicon triacetate was shaken with water, hydrolysis occurred producing acetic acid and a colloidally dispersed ethyl siloxane. The silicon material could be precipitated by removing part of the water by distillation or a rapid precipitation could be had by the addition of ammonium hydroxide to the colloidal product.

The next example describes the preparation of diethyl silicon diacetate from sodium acetate and diethyldichlorosilane.

Example 2.-In a 300 ml., 3-neck flask, equipped with a stirrer and a reflux condenser, was placed a mixture of 19.7 g. of diethyldichlorosilane, 23 g. of sodium acetate and ml. of benzene. The mixture was stirred and heated at about 100 C. for 2-3 hours. The reaction mixture was then filtered and the salt was washed with benzene. Distillation gave a yield of diethyl silicon diacetate, B. P. 60 C. at 1-2 mm. Analytical data:

' Equivalent wt.: Calc. 102, found 103 Molecular wt.: Calc. 204, found 205 When the product was shaken with water it was hydrolyzed to acetic acid and a dispersed diethylsiloxane. Some of the hydrolysis product may also have been in the form of a diethylsilanediol.

The next example describes the preparation of triethylsilicon monoacetate from triethylchlorosilane and sodium acetate.

Example 3.-In a 300 ml., 3-neck flask, equipped with a stirrer and a reflux condenser, was placed a mixture of 18.8 g. of triethylchlorosilane, 11.1 g. of sodium acetate and 50 ml. of benzene. The mixture was stirred and heated at about C. for 2-3 hours. The reaction mixture was filtered and the salt was washed with benzene. Distillation gave a 45% yield of triethylsilicon monoacetate, B. P. 92 C. at 50 mm. Analytical data:

Equivalent wt.: Calc. 1'74, found Molecular wt.: Calc. 174, found 174 The next example describes the preparation of normal propyl silicon triacetate from normal propyltrichlorosilane and acetic acid.

Example 4.In a 300 ml. flask was placed a mixture of 22.2 g. of n-propyl-trichlorosilane, 22.2 g. of acetic acid and 40 ml. of pentane. The mixture was heated, under reflux, at 60-80 C. for 8 hours. The reaction product was distilled and there was obtained a 50% yield of n-propyl silicon triacetate, B. P. 127-131 C. at mm. Analytical data:

Equivalent Wt.: Calc. 83, found 81 Molecular Wt.: Caic. 248, found 251 A colloidal dispersion of the product was made by mixing it with water.

The next example describes the preparation of allyl silicon triacetate from allyltrichlorosilane and sodium acetate.

Example 5.In a 300 ml., 3-neck flask, equipped with a stirrer and a reflux condenser, was placed a mixture of 21.8 g. of allyltrichlorosilane, 33 g. of sodium acetate and 50 ml. of benzene. The mixture was stirred and heated at about 100 C. for 2-3 hours. The reaction mixture was then filtered and the salt was washed with benzene. Distillation gave a 26% yield of allyl silicon triacetate, B. P. 90-95" C. at 1 to 2 mm. Analytical data:

Equivalent weight: Calc. 82, found 84 Molecular weight: Calc. 246, found 241 A colloidal dispersion of the material was obtained when it was hydrolyzed by shaking with water.

The next example describes the preparation of normal butyl silicon triacetate from normal butyltrichlorosilane and sodium acetate.

Example 6.In a 3 liter, 3-neck flask, equipped with a stirrer and a reflux condenser, was placed a mixture of 156 g. of n-butyltrichlorosilane, 203 g. of sodium acetate and 400 ml. of benzene. The mixture was stirred and heated at about 100 C. for 3-4 hours. The reaction mixture was then filtered and the salt was washed with benzene. Distillation gave a 72% yield of butyl silicon triacetate, B. P. 106108.C. at 1-2 mm. Analytical data:

Equivalent Wt.: Cale. 87.5, Found 88.7 Molecular Wt.: Calc. 262, Found 262 Silicon: Cale. 10.7, Found 9.5

A colloidal dispersion of the material was obtained when it was hydrolyzed by shaking with water.

The next example described the preparation of di-n-butyl silicon diacetate from di-n-butyidichlorosilane and acetic acid.

Example 7.-In a 300 ml. flask was placed a mixture of 26.6 g. of di-n-butyldichlorosilane, 15 g. of aceticlacid and 40 ml. of pentane. The mixture was heated under reflux at 60-80 C. for about 8 hours. The reaction product was then distilled and there was obtained di-n-butyl silicon diacetate, B. P. 125l30 C. at 23 mm. Analytical data:

Equivalent Wt.: Calc. 130, Found 130 The next example describes the preparation of ethyl silicon tripropionate from ethyl silicon trichloride and propionic acid.

Example 8.1n a 300 ml. flask, equipped with a reflux condenser, was placed a mixture of 20.5 g. of ethyltrichlorosilane, 27 g. of propionic acid and 40 ml. of pentane. The mixture was heated at 60-80 C. for about 8 hours. The reaction product was distilled there was obtained a 76% yield of ethyl silicon tripropionate, B. P. 1l5-ll7 C. at 1-2 mm. Analytical data:

Equivalent Wt.: Gala. 92, Found 92 Molecular Wt.: Cale. 276, Found 278 silicon: Cale. 10.2, Found 10.4

benzene.

A somewhat cloud solution was obtained when the product was hydrolyzed by shaking with water. Addition of ammonium hydroxide precipitated the colloidally dispersed material.

The next example describes the preparation of diethyl silicon dipropionate from diethyldichlorosilane and sodium propionate.

Example 9.In a 300 ml., 3-neck flask, equipped with a stirrer and reflux condenser, was placed a mixture of 19.7 g. of diethyldichlorosilanc, 26.5 g. of sodium propionate and 50 ml. of benzene. The mixture was stirred and. heated at about C. for 2-3 hours. The reaction mixture was then filtered and the salt was washed with benzene. Distillation gave a 69% yield of diethyl silicon dipropionate, B. P. 81-82 C. at 2 mm. Analytical data:

Molecular Wt; Calc. 232, Found 230 The next example describes the preparation of phenyl silicon triacetate from phenyltrichlorosilane and sodium acetate.

Example 10.--In a 300 ml., 3-neck flask, equipped with a stirrer and reflux condenser, was

placed a mixture of 26.8 g. of phenyltrichlorosilane, 33.1 g. of sodium acetate and 50 ml. benzene. The mixture was heated and stirred at about 100 C. for 2-3 hours. The reaction mixture was then filtered and the salt was washed with benzene. Distillation gave a 66% yield of phenyl silicon triacetate, B. P. 144-146 C. at 1-2 mm.; M. P. 38-39 C. Analytical data:

Equivalent Wt.: Calc. 94, Found 93 Molecular Wt.: Cale. 282, Found 285 A clear solution was obtained when the product was hydrolyzed by shaking with water. The addition of ammonium hydroxide to the solution precipitated the product as a fine white powder.

The next example describes the product obtained by treating normal hexyltrichlorosilane with sodium acetate.

Example 11.In a 100 ml. flask, equipped with a reflux condenser, was placed a mixture of 4.3 g. of n-hexyltrichlorosilane, 5.8 g. of sodium acetate and 25 g. of benzene. The mixture was heated at about 100 C. for 2-3 hours. The reaction mixture was filtered and the salt was washed with Distillation gave a crude sample of n-hexyl silicon triacetate, B. P. 135 C. at 1-2 mm. a

The next example describes the preparation of dimethyl silicon diacetate from dimethyldichlorosilane and sodium acetate.

Example 12.In a 300 ml., 3-neck flask, equipped with a stirrer and reflux condenser, was placed a mixture of 16.1 g. dimethyldichlorosilane, 23 g. sodium acetate and 50 ml. benzene. The mixture was stirred and heated at about 100 C. for 2-3 hours. The reaction mixture was filtered and the salt was washed with benzene. Disillation gave a 60% yield of dimethyl silicon diacetate, B. P. 88-90 C. at 50 mm. Analytical data:

Equivalent Wt.: Calc. 88, found 91 Molecular Wt.: Calc. 176, found 187 The next example describes the preparation of a mixture of butyl silicon acetates.

Example 13.A mixture of silicon chlorides was prepared by adding a solution of one-quarter mole of butyl bromide and one-quarter mole of silicon tetrachloride to one-quarter gram atomic weight of magnesium turnings in ml. of ether.

75 After the reaction had finished there was added 7 to the mixture 100 ml. of benzene and 67 grams of sodium acetate. The ether was removed by distillation and the mixture was heated to about 100 C. for 3 hours. The liquid layer was then decanted and the salt washed with three 50 m1. portions of benzene. 'On distillation there was obtained, after the removal of the benzene, 40 grams of a mixture of silicon acetates. Fractionation of this material produced 20 grams of butyl silicon triacetate.

Equivalent weight: Calc., for butyldiacetoxysilane 102 Equivalent weight: Found, 103

The next example describes the preparation of butyldipropionoxysilane from butyldichlorosilane and propionic acid.

Example 15.In a 300 ml. flask was placed a mixture of 20 grams of butyldichlorosilane, 19 ml. of propionic acid and 40 ml. of pentane. The mixture was refluxed for 6 hours. When the reaction mixture was fractionally distilled there was obtained a liquid boiling at 90 C. at 2 mm.

Analytical data:

Equivalent weight: Calc., for butyldipropionoxysilane 116 Found, 114

The next example describes the preparation of dibutyl silicon dibenzoate.

Example 16.In a 300 ml., 3-neck flask, equipped with a stirrer and a reflux condenser was placed a mixture of 26.6 grams of dibutyldichlorosilane, 20 grams of sodium benzoate and 100 ml. of benzene. The mixture was heated, with stirring, at about 100 C. for 3 hours. The reaction mixture was filtered and the salt was washed with benzene. The benzene was then removed under reduced pressure. The remaining liquid was readily hydrolyzed to a dibutyl silicone and benzoic acid. The product before hydrolysis gave the following results on analysis:

Molecular weight: Calc., for dibutyl silicon dibenzoate 384 Molecular weight: Found, 365

Neutral equiv.: Calc., 192

Neutral equiv.: Found, 212

The next example describes the preparation of butyl silicon triformate.

Example 17.-In a 300 ml., 3-neck flask, equipped with a stirrer and a reflux condenser,

was placed a mixture of 24 grams of butyltr;-

chlorosilane, 40 grams of sodium formats and 100 ml. of toluene. The mixture was heated, with stirring, at 110-120 C. for 4 hours. The reaction mixture was filtered and the salt was washed with toluene. The toluene was removed by distillation under reduced pressure. The remaining liquid had a boiling range of 150-160" C. at 50 mm.

8 Analytical data:

Molecular weight: Calc., for butyl'silicon triformate 220 Molecular weight: Found, 231

Neutral equiv.: Calc., 73

Neutral equiv.: Found, 73

Having thus set forth our invention, we claim:

1. The method of making organo substituted silicon acylates which comprises reacting an organo substituted silicon halide having the formula RuRb SlHY(3-ab) where R and R are selected from the group consisting of alkyl and olefinic hydrocarbon radicals and phenyl, Y is halogen, a is from 1 to 2 and b is from 0 to 1, with a carboxylic acylating agent selected from the group consisting of fatty acids, benzoic acid, the anhydrides and salts of said acids.

2. The method of claim 1 in which the reactants are heated together in the presence of an organic liquid solvent for at least one of the reactants.

3. The method as set forth in claim 2 in which the acylating agent is used in an amount approximately stoichiometrically equivalent to the halogen in the silicon halide.

4. The method as set forth in claim 2 in which the acylating agent is a fatty acid.

5. The method of claim 4 in which at least one organo group of the silicon halide is an alkyl group of from 1 to 6 carbon atoms.

6. The method of claim 4 in which at least one organo group of the silicon halide is an olefinic hydrocarbon group of from 1 to 6 carbon atoms.

7. An organo substituted silicon acylate having the formula RaRb SiHZ(3-ab) in which R and R are selected from the group consisting of alkyl and olefinic hydrocarbon radicals and phenyl, Z is a carboxylic acyl radical selected from the group consisting of fatty acids and benzoic acid, a is from 1 to 2, b is from 0 to 1, and a+b is not greater than 2.

8. An acylate as set forth in claim 7 in which a substituent group attached to silicon is an alkyl group.

9. An acylate as set forth in claim 7 in which a substituent group attached to silicon is an olefinic hydrocarbon group.

10. An acylate as set forth in claim 7 in which the acylate is from a fatty acid.

11. Butyl diacetoxy silane.

12. Butyl dipropionoxy silane.

13. The method of making substituted silicon acylates which comprises heating a butyl silicochloroform with a carboxylic acylating agent selected from the group consisting of fatty acids, benzoic acid, the anhydrides and salts of said acids in the presence of an organic liquid solvent for at least one of the reactants.

14. The method of making substituted silicon acylates which comprises heating an alkyl silicochloroform with a carboxylic acylating agent selected from the group consisting of fatty acids, benzoic acid, the anhydrides and salts of said acids in the presence of an organic liquid solvent for at least one of the reactants.

15. An acylate having the formula RaRb slHZ(3-a-b) in which R and R are alkyl, Z is a fatty acid acyl group, a is from 1 to 2, b is from 0 to l, and a+b is not greater than 2.

16. An alkyl diacyl silane, the acyl group being a fatty acid acyl group.

1'7. A silane as set forth in claim 16 in which 15 the alkyl group has from 1 to 6 carbon atoms.

18. A silane as set forth in claim 16 in which the acyl group is acetyl.

19. A silane as set forth in claim 16 in which the alkyl group has from 1 to 6 carbon atoms and the acyl group is acetyl.

20. A silane as set forth in claim 16 in which the acyl group is propionyl.

21. A silane as set forth in claim 16 in which the alkyl group has from 1 to 6 carbon atoms and the acyl group is propionyl.

22. A silane as set forth in claim 16 in which the acyl group is formyl.

23. A silane as set forth in claim 22 in which the alkyl group has from 1 to 6 carbon atoms.

24. An acylate as set forth in claim 7 in which a substituent group attached to silicon is allyl.

25. An acylate as set forth in claim 7 in which a substituent group attached to silicon is phenyl.

26. An acylate as set forth in claim 7 in which a substituent group attached to silicon is methyl.

CHARLES A. MACKENZIE. MILTON SCHOFFMAN.

REFERENCES CITED The following references are of record in the file of this patent:

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1. THE METHOD OF MAKING ORGANO SUBSTITUTED SILICON ACYLATES WHICH COMPRISES REACTING AN ORGANO SUBSTITUTED SILICON HALIDE HAVING THE FORMULA RAR''B SIHY(3-A-B) WHERE R AND R'' ARE SELECTED FROM THE GROUP CONSISTING OF ALKYL AND OLEFINIC HYDROCARBON RADICALS AND PHENYL, Y IS HALOGEN, A IS FROM 1 TO 2 AND B IS FROM 0 TO 1, WITH A CARBOXYLIC ACYLATING AGENT SELECTED FROM THE GROUP CONSISTING OF FATTY ACIDS, BENZOIC ACID, THE ANHYDRIDES AND SALTS OF SAID ACIDS. 